The Free Speach Clause of the First Ammendment of the United State Constitution States: "Congress hall make no law...abridging the freedom of speech or of the press..."
Six exceptions to the principle on government restrtiction:1. speech that is likely to lead to criminal actions2. "Fighting Words" (insulting enough to fight back).3. obscene words, (that lacks any social or artistic value).4. child porn 5. statements that may, under the constitution, make them liable.6. commercial speech that is pertaining to illegal stuff or "with a degree of supression no greater than is reasonably necessary.
-More info about the legal terms can be found at The National Endowment for the Arts & the Cornell University Legal Information Institute.
